javascript - 如何使 handleChange 方法正确地将用户输入格式化为所需的范围？

Question

我有以下字段，我希望通过根据数据添加前导零和尾随零来使所需的输出采用 XX.xxxxxx 的格式

<TextBoxField
  id="location-latitude-control"
  title="Required: Latitude"
  name="location.latitude"
  value={location.latitude}
  handleChange={this.handleChange}
  handleBlur={this.handleBlur}
/>

我该怎么做才能修复我的 handleChange 方法以正确格式化用户的输入:

handleChange = value => {
  const numsAfterDot = 6;
  const isNegative = value < 0;
  const hasDecimals = value.includes(".");
  let absolute = Math.abs(value).toString();
  if (isNaN(absolute)) return;
  else {
    const split = absolute.split(".");
    let start = hasDecimals ? split[0] : absolute.slice(0, 2);
    let rest = hasDecimals ? split[1] : absolute.slice(2, numsAfterDot)
    start = start.padStart(2, "0");
    rest = rest.padEnd(numsAfterDot, "0");
    const result = `${start}.${rest}`;
    return isNegative ? `-${result}` : result;
  }
}

纬度的预期行为:

"7.0" should convert to "07.000000"
"12.1234561" should convert to "12.123456"

Answer 1

您可以使用 Math.pow 和 toFixed。

let handleChange = (val) => {
  const len = (+val).toString().length;
  if (len > 1) {
    const pow = val > -1 ? len - 2 : len - 3;

    return "" + (val / Math.pow(10, pow)).toFixed(6);
  }
  return "0" + (+val).toFixed(6);
};

console.log(handleChange("7.0")); //07.000000
console.log(handleChange("123456789")); //12.345679
console.log(handleChange("12")); //12.000000
console.log(handleChange("1")); //1.0000000
console.log(handleChange("-123")); //-12.300000
console.log(handleChange("1234")); //12.340000